Firearm



June Z1; 1932.

H. RoMBERG E1' AL 1,864,374

FIREARM Filed Jan. 5, 1932 'NV `:v Hem/M Hame SEL-5R fle/*777.27771 $5024 ATTD man( l y Patented .lune 21, 1932 sul HEINRICH ROMBERG AND HERMANN SCHULER, OFDUSSELDORF, GERMANY, ASSIGNORS A T0 BHEINISCI-IE METALLWAAREN UND` MASCHINENFABRIK, OF DUSSELDORF- DERENDORE, GERIVIANY, A CORPORATION OF GERMANY `rrnnrinnr l Application led January 5, 1932, Serial No.

nearer objects behind shelters or covers. For

this purpose the part ot the barrel having turrows or grooves is provided with lateral holes `which may be more or less throttled by means of a control member to conduct away a smaller orI greater portion of the.

driving gases,` so that this portion of the eases is prevented from acting upontlie projectile. By drawing oi gases in such a manner at the middle or front part of the barrel,

a very small reduction oi' the starting ver locityot the projectile may be obtained only.

as the driving gases in the shape of a closed jet pass with great velocity over the drawing oii' holes without the desired amount of gas being conducted away laterally. Moreover the frontedges of' the holes, provided in the` barrel and acting like a knife, scrape chips ofi' the projectile passing along andsuch chips accumulate in the holes which therefore soon become clogged.

" To be able to use in a weapon cartridges i havingan excessive charge, the part of the cartridge chamber surrounding the projectile behind the turrows or grooves has already been provided with holes, and by means ot the annular space or radial clearance provided in this manner between the projectile and the wall of the chamber, a portion or" the driving gases has been drawn `ott bv way ot the front portion of the barrel without being used. These gases, passing along the projectile in the torni ot a blow pipe flame, cause, however, a strong burning out of the barrel, and moreover, the projec tile is not guided at the beginning of its movement. j

According to the invention the driving `gases are drawn 0E by means of an annular space or radial clearance in the cartridge chamber which space surrounds the projec- 584,B55, and in Germany January `9, 1931.

tile behind the rear end of the fuirows or grooves and to which the channels leading outwards or an additional space are connected. The projectile, extending now already before the firing partially over the drawing ofi portion in the barrel, slides, at the beginning` of its movement completely over the holes, without forming chips and a sufficient amount of the driving gases escapes, as these gases are developed only after the drawing oit holes have been uncovered and therefore'have still a very small forward velocity. The gases passing through the annular space may be conducted into a closed additional space which, acting as an en largement of the combustion space, reduces themaximum gas pressure and therefore the medium gas pressure also. The driving gases may also directly be conducted into the atmosphere by way ot an intermediate chamber and in this way they are absolutely prevented from acting upon the projectile. Particularly suitable for the drawing oif of the driving gases is an annular space or radial clearance in the barrel in front of the cartridge shell the Width of which may be adjustedfor allowing a smaller or greater amount of gas to pass through in the time unit and which also may be completely closed.- V Y ln the accompanying drawing the invention is shown by way of example in connection with the barrel of an automaticmachine gun a portion of which is illustrated in` longitudinal section.

The barrel is composed of two parts, a hind or rear part a, containing the cartridge chamber and a'fterwardscalled cartridge chamber, and a front portion b in which the furrows or grooves b1 are cut. The part b is screwed into a female thread al of the cartridge chamber `an and may be, by means of a locking device di, d2, adjusted and fixed therein from a position in which the front face b2 of the outer conical hind end b3 of the barrel part b is in contact with a corresponding counter face a2 of the cartridge chamber to positions in which a space of different width is formed between these two surfaces. The mouth piece a3 of the cartridge chamber is hollow, so that a free annular space e remains surrounding the hind or rear vend b3 of the portion Z2 providedV with the furrows or grooves 1.v r)This space e forms the continuation of the space c. A plurality of bores ai, provided around the mouth piece a3 and extending in the direction of the barrel or in a somewhat outwardly inclined direction, lead from the' space e'into the atmosphere or into a jacket surrounding the barrel.

If projectiles are to be fired with the nor-P mal startingvelocity in a sweeping or scour-A ing trajectory, the portion of the barrel provided with the furrows or grooves 51' is screwed into the cartridge chamber a until its hind or rear face b2 contacts with the counter face a2 of the cartridge chamber a in which position the part b is locked against rotation by means of the locking device d1, d2. Then all the gases developed by the driving charge of the cartridge will be active to propel the projectile. To obtain a more curved trajectory having a steeper angle of incidence, the portion o of the barrel, having the f'urrowsfor grooves 1, is, by Yscrewing out, shifted to the front in the cartridge chamber a, so that between'the surface b2, a2 of these two parts an annular space c or radial clear-V ance fof determined Width is formed through Which, according to the width adjusted, a smaller or greater portion of the driving gases developed behind the projectile is, partially used only or n-ot usedat all, passed into the space e and from there,by way of the holes (Z4, into the atmosphere. The effect of the different positions of the barrel portion Z) in the cartridge chamber a and ofthe space c which is formed by these two par-ts upon the starting velocity of the projectile ymay be indicated on the outside by means of a suitable indicating device, so that the proper adjustment may be obtained. A width of the slot of about 0.8 mm. is sufficient to reducev the normal lstarting velocityV of an infantry projectile to about half the velocityi The adj ust-,ability of thecross section of the drawing oif channels and also of 'the width of the slot c is not absolutely necessary. In the case of weapons having anexchangeable barrel, besides the normal one-part barrels, barrels provided with. a fixedly adjusted space thread` at the hind or rear yend of said barrel portion fitting said female thread, said barrel portion having a conical rear end extending into a correspondingly shaped portion of said cartridge' chamber in such a manner, that an annular space is formed between said parts which communicates with bores provided in said cartridge chamber opening into the at` mosphere. Y Y l 2. In a fire arm having a device for altering the starting velocity of the projectile'by conducting a portion of the driving gases out o f the barrel, a cartridge chamber, a female thread at the front end of said chamber, a

barrel portion having furrows orV grooves, a thread at the hind or rear end of said barrel portion fitting said female thread, said barrel portion having a conical rear end extending into a correspondingly shaped portion of said cartridge chamber in such a manner, that an annular space is formed between said parts which communicates with an additional space formed between the inclined surfaces Vof both saidrpar'ts and whichin turn communicates withsaid bores provided in said cartridge thread at the hind or rear end of said barrel' portion fitting said female thread, said barrel portion having a conical rear end extending into a correspondingly shaped portion of said cartridge chamber, a locking member carried by said cartridge chamber and a plurality ef locking members provided at said barrel portion and cooperating with said first mentioned locking member toA fix the two parts screwed together in the adjusted position against relative rotation. v

In testimony whereof we affix our signatures.

HEINRICH ROMBERG. HERMA-NN SCHULER.

of a determined width between the portionV 'i having the furrows or grooves and the cartridge chamber'may be carried with which serve the purpose of firing standard projectiles 4under a perfectly determined trajectory altered with regard to thenormal trajectory. -We claim: v Y Y Y 1. IIn a Vfire arm having'a device-for altering lthe starting velocity of the projectilefby conducting a portion of the driving gases out of the barrel, a cartridge chamber, a 'female thread -at the frontend of said chamber, aV barrel portion having furrows or grooves, a 

